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【目的】构建禽致病性大肠杆菌(Avian pathogenic Escherichia coli,APEC)rmlA基因缺失株,研究该缺失株的生物学特性。【方法】利用Red重组系统构建rmlA缺失株;比较野生株与缺失株在生长特性、运动性和生物被膜形成能力等方面的差异;运用Real-time PCR技术,比较野生株与rmlA缺失株对APEC部分毒力基因转录的影响。【结果】rmlA缺失株,不影响APEC的生长和运动特性,但生物被膜形成能力显著增强,且使luxS、irp2基因转录水平分别上调2倍、1.8倍,iucD、fyuA则下调25倍。【结论】APEC的rmlA基因可以影响禽致病性大肠杆菌的生物被膜形成能力及部分毒力基因的转录水平;而对APEC的生长、运动特性没有影响。
【Objective】 To construct the rmlA gene deletion mutant of avian pathogenic Escherichia coli (APEC) and to study its biological characteristics. 【Method】 The rmlA deletion mutant was constructed by using the Red recombination system. The differences in growth characteristics, motility and biofilm formation between the wild strain and the deletion mutant were compared. Real-time PCR was used to compare the effect of wild strain and rmlA deletion mutant on APEC Effects of partial virulence gene transcription. 【Result】 The rmlA deletion strain did not affect the growth and movement characteristics of APEC, but the biofilm formation ability was significantly enhanced. The luxS and irp2 gene transcription levels were up-regulated by 2-fold and 1.8-fold, respectively, while iucD and fyuA were down-regulated by 25 folds. 【Conclusion】 APEC rmlA gene can affect the biofilm formation ability of avian pathogenic Escherichia coli and the transcriptional level of some virulence genes, but has no effect on the growth and motility of APEC.